Some attributes (i.e., characteristics or features) of a material can be determined (e.g., measured) with an appropriate instrument. For example, various models of instruments for non-destructively measuring the thickness of a film or layer (i.e., coating) of copper as electroplated on a printed circuit board are sold by Oxford Instruments Coating Measurement, a part of the Oxford Instruments Analytical division of Oxford Instruments plc (hereinafter referred to as “Oxford”), which has a place of business at 945 Busse Road, Elk Grove Village, Ill. 60007, U.S.A. Typically, during the manufacture of a printed circuit board, it is desirable to know whether or not the design specifications are being met by, inter alia, the copper coating(s) on a substrate component of the printed circuit board. In particular, it typically is important to know the thickness of the copper coating(s) within some sufficient range of precision and accuracy in order for the manufacturer to determine whether or not the copper thickness on a portion or portions of the printed circuit board is within the allowable manufacturing tolerances as established by the design.
Different systems can be employed in an instrument to measure a feature, such as a coating thickness. These systems can include, for example, the use of a probe employing magnetic induction, eddy currents, or micro-resistance methods or techniques. Selection of the technique to be employed can depend on various factors (e.g., the type of coating material, geometric configuration of the coating and substrate, desired accuracy and precision, size of the area being measured, range of thickness to be measured, efficiency of use, ambient environmental conditions, and cost). Such a probe may employ one or more contact members for engaging the coating, and the probe may be a separate, hand-held probe, or may be mounted in a stationary device.
Although Oxford markets probes that are designed for various applications and that function exceptionally well in systems efficiently performing measurement analyses (such as measurement of a coating thickness), it would be desirable to provide improved probe features that would result in, or accommodate, even better performance, greater functionality, more versatility, ease of use, ease of manufacturing, lower cost manufacture, and/or improvement in accuracy, precision, efficiency of use, tolerance of ambient environmental conditions, and durability.
It would be particularly advantageous to provide an improved probe that optionally could be selectively configured with a different tip geometry to maximize accuracy and precision in various applications and/or that optionally could accommodate replacement of a worn or broken component.
It would also be beneficial to provide an improved probe permitting the user or operator to better observe the end of the probe and the adjacent portion of the material where the particular attribute of the material (e.g., thickness) is to be determined by the use of the probe.
Also, with a probe of the type that employs a pin or pins for engaging or contacting a material (e.g., a copper coating), it would be desirable to provide an improved probe that has greater pin stability so as to minimize deleterious effects on measurement precision.
The present invention provides an improved probe which can accommodate designs having one or more of the above-discussed benefits and features.